Hull zinc

[Steve Laume]

I was wondering if anyone has added a hull zinc to their boat.

Raven only has room for a perry nut type zinc on the end of the prop shaft. I don't go through it too fast but it would be nice to have a more substantial zinc. It seems like a hull zinc could be added near the bronze bonding plate and tied to it. I suppose it could even be drilled and tapped into it. Any thoughts on this would be appreciated.

One of these is what I had in mind, Steve.

https://www.boatzincs.com/hull_bolt-on.html

[John Stone]

Steve
I’m not an expert on zincs. Since I don’t have a prop shaft I don’t have a place to install one. I asked a very knowledgeable and well respected marine professional that I trust how I should do it. He told me that if it is not located on a metal, simply attaching a zinc to the hull will serve no purpose.

I have no zinc on my boat since there is nothing to attach it to except fiberglass. If you learn something different I’d appreciate hearing about it.

[Steve Laume]

At first, I was thinking about mounting it in the prop aperture, below the prop but if it every parted ways with the boat it would go directly into the prop. I have had the perry nut come off and it just goes on it's way. So I don't think I would chance that location.

I had been looking at the area, directly behind the grounding plate as I could tie it to the plate. Now I have been thinking about mounting it in the same location as the grounding plate but on the opposite side of the hull. It would be pretty simple to bolt it on in that location as I can get into the bilge to address the fasteners. Then it would be a simple matter of running a heavy copper wire over to the grounding plate where all the other bonding wires live. That would require two more bolt holes below the waterline but I don't really worry too much about drilling holes in the boat. This might be one place where 5200 would be appropriate.

Having a big healthy zinc would give me great peace of mind, Steve.

[Jim Davis]

Steve

Having used hull zincs on my boats a couple observations. Your location sounds good however you might want to consider copper strap rather than wire. Also be careful sealing the bolts coming through the hull. Sealants are also insulators and you are dealing with very low voltage and current. Assuming that you don't have any major electric leakages you will be able to get away with wire brushing the zinc at each haul out. Never get paint on it. Also to protect the prop you should add a jumper across the engine drive flange (especially if you have a flex copling or drive saver). Be aware that there is some electrical resistance in an engine drive train due to the oil coating all moving parts. I did use either a shaft zink or Perry Nut in addition.

The reason I used hull zincs was based on neighbors in a community marina situation.

[Nebe]

A hull zinc should be “bonded” to all through hulls in a bonding circuit. I just took this pic from Nigel Caldera book “boat owners mechanical and electrical manual”.

[Keith]

Hi Steve,

It looks like according to Nigel connecting yours to the ground plate is the right thing to do.

Keith